[FFmpeg-devel] [PATCH 1/2] avcodec/wrapped_avframe: implement wrapped_avframe decoder

[Paul B Mahol]

On 11/10/15, Michael Niedermayer <michael at niedermayer.cc> wrote:
> On Tue, Nov 10, 2015 at 04:54:17PM +0700, Muhammad Faiz wrote:
>> On Mon, Nov 9, 2015 at 11:22 PM, wm4 <nfxjfg at googlemail.com> wrote:
>> > On Mon, 9 Nov 2015 08:03:54 -0800
>> > Muhammad Faiz <mfcc64 at gmail.com> wrote:
>> >
>> >> From 4dcbda2e585404d2d79d5afcdc13fcb699f6f158 Mon Sep 17 00:00:00 2001
>> >> From: Muhammad Faiz <mfcc64 at gmail.com>
>> >> Date: Mon, 9 Nov 2015 15:55:13 +0700
>> >> Subject: [PATCH 1/2] avcodec/wrapped_avframe: implement
>> >> wrapped_avframe
>> >>  decoder
>> >>
>> >> fix ticket #4985
>> >> for use in avdevice/lavfi
>> >> ---
>> >>  libavcodec/Makefile          |  1 +
>> >>  libavcodec/allcodecs.c       |  2 +-
>> >>  libavcodec/version.h         |  2 +-
>> >>  libavcodec/wrapped_avframe.c | 32 ++++++++++++++++++++++++++++++++
>> >>  4 files changed, 35 insertions(+), 2 deletions(-)
>> >>
>> >> diff --git a/libavcodec/Makefile b/libavcodec/Makefile
>> >> index 68a573f..c60d512 100644
>> >> --- a/libavcodec/Makefile
>> >> +++ b/libavcodec/Makefile
>> >> @@ -577,6 +577,7 @@ OBJS-$(CONFIG_WMV2_ENCODER)            += wmv2enc.o
>> >> wmv2.o \
>> >>                                            msmpeg4.o msmpeg4enc.o
>> >> msmpeg4data.o
>> >>  OBJS-$(CONFIG_WNV1_DECODER)            += wnv1.o
>> >>  OBJS-$(CONFIG_WS_SND1_DECODER)         += ws-snd1.o
>> >> +OBJS-$(CONFIG_WRAPPED_AVFRAME_DECODER) += wrapped_avframe.o
>> >>  OBJS-$(CONFIG_WRAPPED_AVFRAME_ENCODER) += wrapped_avframe.o
>> >>  OBJS-$(CONFIG_XAN_DPCM_DECODER)        += dpcm.o
>> >>  OBJS-$(CONFIG_XAN_WC3_DECODER)         += xan.o
>> >> diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
>> >> index 9f60d7c..3260927 100644
>> >> --- a/libavcodec/allcodecs.c
>> >> +++ b/libavcodec/allcodecs.c
>> >> @@ -342,7 +342,7 @@ void avcodec_register_all(void)
>> >>      REGISTER_DECODER(VP9,               vp9);
>> >>      REGISTER_DECODER(VQA,               vqa);
>> >>      REGISTER_DECODER(WEBP,              webp);
>> >> -    REGISTER_ENCODER(WRAPPED_AVFRAME,   wrapped_avframe);
>> >> +    REGISTER_ENCDEC (WRAPPED_AVFRAME,   wrapped_avframe);
>> >>      REGISTER_ENCDEC (WMV1,              wmv1);
>> >>      REGISTER_ENCDEC (WMV2,              wmv2);
>> >>      REGISTER_DECODER(WMV3,              wmv3);
>> >> diff --git a/libavcodec/version.h b/libavcodec/version.h
>> >> index 1e21f15..5eecf5b 100644
>> >> --- a/libavcodec/version.h
>> >> +++ b/libavcodec/version.h
>> >> @@ -29,7 +29,7 @@
>> >>  #include "libavutil/version.h"
>> >>
>> >>  #define LIBAVCODEC_VERSION_MAJOR  57
>> >> -#define LIBAVCODEC_VERSION_MINOR  15
>> >> +#define LIBAVCODEC_VERSION_MINOR  16
>> >>  #define LIBAVCODEC_VERSION_MICRO 100
>> >>
>> >>  #define LIBAVCODEC_VERSION_INT
>> >> AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
>> >> diff --git a/libavcodec/wrapped_avframe.c
>> >> b/libavcodec/wrapped_avframe.c
>> >> index 13c8d8a..185a1a2 100644
>> >> --- a/libavcodec/wrapped_avframe.c
>> >> +++ b/libavcodec/wrapped_avframe.c
>> >> @@ -32,6 +32,8 @@
>> >>  #include "libavutil/buffer.h"
>> >>  #include "libavutil/pixdesc.h"
>> >>
>> >> +#if CONFIG_WRAPPED_AVFRAME_ENCODER
>> >> +
>> >>  static void wrapped_avframe_release_buffer(void *unused, uint8_t
>> >> *data)
>> >>  {
>> >>      AVFrame *frame = (AVFrame *)data;
>> >> @@ -71,3 +73,33 @@ AVCodec ff_wrapped_avframe_encoder = {
>> >>      .encode2        = wrapped_avframe_encode,
>> >>      .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
>> >>  };
>> >> +
>> >> +#endif
>> >> +
>> >> +#if CONFIG_WRAPPED_AVFRAME_DECODER
>> >> +
>> >> +static int wrapped_avframe_decode(AVCodecContext *avctx, void *data,
>> >> +                                  int *got_frame, AVPacket *avpkt)
>> >> +{
>> >> +    int ret;
>> >> +
>> >> +    if (avpkt->size != sizeof(AVFrame))
>> >> +        return AVERROR(EINVAL);
>> >> +
>> >> +    if ((ret = av_frame_ref((AVFrame *) data, (AVFrame *)
>> >> avpkt->data)) < 0)
>> >> +        return ret;
>> >> +
>> >> +    *got_frame = 1;
>> >> +    return avpkt->size;
>> >> +}
>> >> +
>> >> +AVCodec ff_wrapped_avframe_decoder = {
>> >> +    .name           = "wrapped_avframe",
>> >> +    .long_name      = NULL_IF_CONFIG_SMALL("AVFrame to AVPacket
>> >> passthrough"),
>> >> +    .type           = AVMEDIA_TYPE_VIDEO,
>> >> +    .id             = AV_CODEC_ID_WRAPPED_AVFRAME,
>> >> +    .decode         = wrapped_avframe_decode,
>> >> +    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
>> >> +};
>> >> +
>> >> +#endif
>> >
>> > This is very dangerous. You get potentially security relevant bad
>> > behavior if you get anyone to force a demuxer/decoder on an untrusted
>> > input file.
>>
>> OK, this makes segfault on my machine (120 = sizeof(AVFrame)/4 on my
>> machine)
>> ffmpeg -codec wrapped_avframe  -pixel_format rgba -f rawvideo -s 120x1
>> -i input.mkv -f null -y /dev/null
>
> maybe in addition to any other saftey features
> "-codec wrapped_avframe" could be checked for and forbidden in
> libavformat, or does this have any safe use ?
>

Allowing it in single situation. Is this doable?

>
> [...]
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
> What does censorship reveal? It reveals fear. -- Julian Assange
>